I just got an IR module for my HP-41CX. Unfortunately it does not seem to work.

I have an Advantage module in port 1 and that's it. I have tried the IR module in the other ports but the calculator does not seem to recognize it. It does not show up in the catalog and the commands are not recognized.

I saw a bit of corrosion on the contacts of the IR module and cleaned them off but that did not help.

Ahh. After playing around some more, I have gotten the IR module to work. The problem appears to be with the calculator and slots 2 & 4. If I have the Advantage module and the IR module in slots 1 & 3, all is good. If I have them in 2 or 4 they are not recognized.

The calculator looks really clean - no corrosion on the contacts. What other types of issues could cause two of the slots to be non-recognized?

Regarding my 'oscilation' :-), it has a quite long 1/f (f = 9.56e-8Hz) of around 4 months with a some 1/4 duty cycle at the East (Canary Islands) side and remaining 3/4 on the West (Dominican Republic) side.

I'm however on-line most of the time and my inbox is happy to receive your messages ;-)

Back to the original thread and the 'post repair'; unscrewing them will more like cause no harm whatsoever and, since you have (want) to fix it, it is mandatory to take them apart, so...

Although Ángel's comment on the 'definitive' metal posts replacement is undoubtly true, there are many cases in which less severe repair procedures may lead to good reliable results.

Once you've removed them, if you dont feel confident on the acctions to take to fix the problem yourself just post here some hi-res pics of the damaged part so others can have a clear idea and offer convenient advice.